Emergency shutdown valves perform the work of bringing the process to a safe state in the event of a hazardous condition. They must be periodically tested, because, unlike other valves, they may sit dormant for a long time.
This 2:22 YouTube video, Emerson TopWorx DX PST with HART 7, explains how this partial stroke and emergency shutdown valve controller controls and monitors these shutdown valves. To test the capability of the valve to perform its safety action, the valve controller can partially stroke the valve that maintains its open or closed position for an extended time.
A partial stroke test (PST) verifies the functionality of critical valves that must be in their fail position during an emergency. Increasing the frequency of partial stroke testing (i.e. reducing the proof test interval) improves the SIL (Safety Integrity Level) that the system can achieve through a reduction in the PFDavg (Average Probability of Failure on Demand). These partial stroke tests can be performed without shutting down or disrupting the process. In an emergency, the ESD function overrides partial stroke testing and the valve moves to its fail position.
Emerson’s TopWorx brand portfolio of products provides engineers and operators the ability to quickly share critical plant floor data, enabling effective collaboration and predictable maintenance while helping to avoid costly downtime.
Our TopWorx DX PST with HART 7 provides a simple, integrated approach that allows easy installation and calibration while meeting all global certifications. This user-friendly device is a smart, adaptive, and reliable solution that provides preventative diagnostics for critical applications.
Designed to improve efficiency, the DX PST can be used to effectively schedule and predict maintenance as it seamlessly integrates with existing control systems to build an extra layer of information that ensures detailed valve data, trends, and diagnostics are monitored and tied into the IIoT.
In addition, the partial stroke testing (PST) safety feature provides redundancy to ensure plant safety. The local PST button enables operators to perform partial stroke tests without the need and expensive additional equipment. Each unit is certified for operation in harsh and hazardous applications and supports multiple handheld devices with integrated SOV and open terminals options allowing an additional pressure transmitter or up to two pressure switches. With the ESD feature ensuring the valve will fully close and halt all processes upon detection of an emergency, the DX PST provides unmatched reliability.
To further ensure safe operation, our comprehensive solution is SIL 3-capable and available with integrated 1oo1, 1oo2, or 2oo2 architecture, compatible with ASCO RCS, and available with industry-leading GO Switch technology for sensor redundancy. Users could also set alarms for events and an upset condition. The device overrides the partial stroke test and will perform an emergency shutdown to prevent a critical failure.
Emerson’s TopWorx DX PST with HART 7 is the ideal device for partial stroke test and emergency shutdown to ensure plant safety. And just another Innovative TopWorx solution to provide variety, flexibility, and options for our valued customers.
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Join us at the October 24-28 Emerson Exchange conference in the Dallas-Fort Worth, Texas area to see a range of safety shutdown valve solutions including the TopWorx DX PST valve controller.
The post Partial Stroke Tests and Diagnostics for Emergency Shutdown Valves appeared first on the Emerson Automation Experts blog.
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